Thomas & Betts LTBUS04L-C LFMC CMP UL 1IN BLU 30M/100FT

It's 1 inch trade size liquid tight flexible metallic conduit, supplied in a 100 ft (30 m) coil. One roll covers a single 100 foot pull, so for longer runs or multiple machine drops plan your quantity off that 100 ft figure rather than assuming a cut-to-length spool.

That's exactly what liquid tight flexible metallic conduit is for. The jacket seals the steel core against water, so it's the standard choice for the final flexible connection to rooftop HVAC units, pumps, and outdoor motors where vibration rules out rigid pipe. Use liquidtight fittings at both ends; an ordinary flex connector breaks the seal.

The difference is the core. The LTBUS04L-C has a galvanized steel spiral under the jacket, which resists crushing and impact and can carry fault current. LFNC is all plastic, lighter and cheaper, but offers no metal raceway and no mechanical protection to speak of, so it needs a grounding conductor pulled and is limited in where it can be run. For machine whips, motor connections and anything exposed to physical damage, go metallic.

The blue jacket on the LTBUS04L-C is a color-coding convention, not a different construction. Contractors use colored liquidtight to keep circuits visually separated in the field, low voltage versus line voltage, or one system versus another, so an electrician tracing a panel can tell at a glance what a whip belongs to. The core is the same galvanized steel.